The Heroine is My Stepsister, and I'm her Final Boss - Chapter 34: A vision

On his coming-of-age day, Argolaith’s mistake bound him to a mystical magic unseen in the world. As his powers grow, they threaten to reshape the realm—but can he master them before they bring ruin?

This legend tells the tale of the protagonist, Kuroki summoned to protect the demon king from the hero.

Kuroki, unbeknownst to him, suddenly came to another world. He was summoned by the demon king, Modes. The territory which the demon king overrules was in the midst of being destroyed because of the hero. He had no choice but to bow before Kuroki.

“Please save us, Savior Dono!”

Kuroki nodded, deciding to save the demon king due to an unexpected turn of event.

He chose her out of curiosity, and she chose him for a good sleep.In this one-year hidden marriage, they agreed to take what they needed and have only pleasure without love. But the reality was that he was very domineering. He could bully her, but if anyone else did the same, they would face severe consequences.Many people felt sorry for him and thought that she didn't deserve him. However, they discovered that her real identities were stunning and extraordinary.She was a genius hacker, a skilled miracle doctor, and even a deadly ghost...Now, people felt sorry for her. How could an astonishing woman like her marry a disabled man?Suddenly, a man who had been in a wheelchair for several years stood up and revealed the business empire he had built during those years.Later on, people started to envy the couple's talent and beauty.While the heavens favored them, she suddenly realized that in his heart, she was nothing more than a substitute...Love was just like poison hidden in sugar. If you believe in it, you lose...

This world has Fox Fairies, River Gods, Water Monsters, Great Demons and Cultivators who seek immortality.